supply of set of items for airflow make pressurized flush system of lhbcoaches. items & quantity: 1. 1/4 - 5/2 push-pull special return valve of airflow makeor equivalent - 01 nos. 1/2 - 2/2 nc external pilot operated special valve of airflowmake or equivalent - 01 nos. note: equivalent means it should be in same shape andsize, material, and able to fit in existing airflow make pressurised flush system oflhb coaches.